216 M. B. WELCH. 



ing" usually occurs in 30%, leaving a small residue finally 

 soluble in 70% alcohol. 



The observations given are sufficient to indicate the great 

 variability in the behaviour of the oil in the glands under 

 the different species. Variation also occurs even in the 

 one species, for example in the final solubility, thus seem- 

 ing to indicate differences, within limits, of the oil product. 



There are still several interesting and unsolved points 

 awaiting investigation, and these I hope to deal with in a 

 later paper. 



In conclusion I wish to record my indebtedness to Mr. 

 R. T. Baker, f.l.s., Curator, Technological Museum, for 

 the great assistance he has given me at all times in collect- 

 ing the data for this paper. 



EXPLANATION OF PLATES. 



Plate XL 



Eucalyptus Moorei Maiden and Cambage. 



Cross section of a portion of a mature leaf near the edge. The 

 oil glands are in this species situated towards either epidermis and 

 are confined to the two palisade zones, never extending across the 

 narrow intermediate spongy tissue. The glands are commonly 

 flattened in a direction parallel to the leaf surface. Three 

 prominent bicollateral vascular bundles are indicated by the red 

 stained tissue. x 55. 



Plate XII. 

 Eucalyptus SmitJiii R. T. Baker. 

 a. H orizontal section of a young leaf below the epidermis, showing 

 arrangement of the oil glands in the leaf tissue. The glands are 

 in various stages of development, and the separation from the 

 interior wall of the cavity of the cells containing the oil in very 

 minute globules, is seen. x 60. 



